Fuel Injectors
Thread Starter
Instructor
Joined: Dec 2009
Posts: 183
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From: J.C. MO
Fuel Injectors
I just charged my C6 and need injectors, I am pretty sure that I will be going with FIC injectors. My question is if I get 60 or 80lb injectors rated at Ford's pressure, how would I compensate for the difference in flow in the inj. flow rate table using HP Tuners?
Le Mans Master
Joined: Aug 2002
Posts: 8,472
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From: Houston TX
St. Jude Donor '11
The stock table maxes out at 63.5#/hr so you end up having to live with lower flow numbers than what are actual. So since the fuel flow is artifically low you have to adjust any airflow or airmass tables accordingly.
So if you go with 60# @ 3 bar of fuel pressure then that is actually ~69.3# at 0 kPa of manifold vacuum (atmospheric) and 75.9# @ 80 kPa of manufold vacuum. So you have to scale 75.9 down to 63.5 in the IFR table which is lowering it by ~20% so you need to look at any tables associated with airflow or airmass and reduce them by 20% as well. The spark tables are different. You need to look at each row and see what the scaled numbers should be. So @ .6 g/cyl airmass is really .6x.8=.48 so the spark values you have in the .6 row need to go into the .48 row.
So if you go with 60# @ 3 bar of fuel pressure then that is actually ~69.3# at 0 kPa of manifold vacuum (atmospheric) and 75.9# @ 80 kPa of manufold vacuum. So you have to scale 75.9 down to 63.5 in the IFR table which is lowering it by ~20% so you need to look at any tables associated with airflow or airmass and reduce them by 20% as well. The spark tables are different. You need to look at each row and see what the scaled numbers should be. So @ .6 g/cyl airmass is really .6x.8=.48 so the spark values you have in the .6 row need to go into the .48 row.
Le Mans Master
Joined: Aug 2002
Posts: 8,472
Likes: 38
From: Houston TX
St. Jude Donor '11
Even 60#'ers that were rated at 4 bar of fuel pressure will be flowing more than 63.5# when under manifold vacuum (I think). While this is not a huge problem as it's only in high vacuum that you'll probably never see, the bigger problem is the depending on your horsepower goals you may not have enough injector there. As stated 60's rated at 3 bar (which most are) flow almost 70 at 4 bar where our cars run. I run 3 bar 60's and I think I see ~80% duty cycle. My advice would be to get 80's and then scale them down. The tables you need to scale are talked about here: http://www.hptuners.com/forum/showthread.php?t=15293
Safety Car
Joined: Feb 2008
Posts: 3,712
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From: TEXOMA
St. Jude Donor '08-'09
if you plan on ever using 80's just go ahead and scale your tune by 50% now.. if staying within the limits of the 60's, then just scale it 20% so not to loose too much upper spark.
-Carl
-Carl
